1. Field of the Invention
Generally, the invention relates to mechanical picking finger assemblies. More specifically, the invention relates to such assemblies which are selectively displaceable in response to external pressures as utilized for harvesting of fruit from trees.
2. Description of the Prior Art
Numerous methods exist to harvest the various fruits currently being cultivated. A first group of such methods employ various mechanical devices which provide for a completely mechanical severing of the individual fruit from a tree. A second group of such methods employ various mechanical devices which provide assistance to individual human pickers during a picking procedure to sever the fruit from the tree. This group generally is limited to mechanical devices which may be held by the human picker during the picking procedure. A third method, specific to the type of fruit being harvested, involves the physical picking of the fruit from the tree by individual human pickers without utilization of any mechanical device.
Referring now specifically to citrus fruits, currently the vast majority of such fruit is harvested by being hand picked by people. This harvesting technique has changed little over the years. Pickers grasp individual citrus fruit members and exert a twisting action, a pulling action or a combination of a twisting and pulling action thereon to separate the fruit from the tree. Then, the picker places the severed fruit in a collection bag. This process is repeated until the collection bag has a desired quantity of picked fruit therein. At this point the contents of the collection bag are deposited into a secondary collection container of sufficient dimensions to contain a larger quantity of the picked fruit than that contained by the collection bag. While certain fruit on a tree is accessible while the picker stands on the ground, certain fruit on the tree may only be accessed by elevating the picker above ground level. The most common method of providing such elevation of the picker is by placing a ladder against the tree while the picker ascends the ladder. It is common practice in the industry to apply various chemicals to the tree and/or surrounding ground at various times prior to harvesting the crop. Therefore, chemicals may remain on the tree during the harvesting operation. As can be readily seen, the current method of manual harvesting of citrus fruit is time consuming and exposes the picker to dangerous conditions, including those during the period of time while the picker is elevated above ground level as well as possible exposure to chemicals.
Certain types of fruit are more adapted to such mechanical harvesting than other types of fruit. Reference is now made to machines which harvest fruit under the above identified method where there exists a completely mechanical severing of the fruit from the tree. The art is rich with such machines designed to harvest fruit by severing the fruit from fruit trees. Such machines generally employ one of two severing methods. The first method involves producing a `shaking action` within the canopy of the tree. This `shaking action` may involve grasping a portion of the tree and generating the desired `shaking action` on the entire tree or may involve insertion of one or more members into the canopy wherein the member or members produce the desired `shaking action` to the canopy without statically engaging, or otherwise grasping, a portion of the tree. The second method involves engaging individual fruit members, or engaging individual connecting stems, and producing a severing action between the individual fruit and the tree.
Without regard to the severing method employed, there exist three strong desires which need to be fulfilled in order for the specific harvesting machine to be commercially accepted within the industry. The first desire is to avoid unnecessary damage to the tree during the harvesting of the fruit attached thereon. This desire relates to actual damage to the tree as well as incidental damage as exampled by removal of immature, or second crop, fruit from certain fruit trees which begin to produce the second crop prior to harvesting of a first mature crop. The second desire is to harvest an extremely high percentage of the mature fruit from each of the trees. The third desire is that the harvesting performed, which satisfies the above two desires, must be economically competitive compared to existing harvesting techniques.
Various deficiencies exist with machines which rely upon the severing action principle. Generally, these machines are referred to as canopy penetration machines which utilize rods with picking members, sometimes referred to as hooks, extending therefrom. Due primarily to the picking members utilized by these machines, these machines also universally have a tendency to damage the tree during harvesting. Additionally, these machines tend to leave an unacceptable quantity of fruit on the tree.
In the prior art we find numerous attempts to provide for a mechanical harvesting of fruit from trees. Several of these attempts have relied upon a `penetrate and engage` method whereby a probe or arm is inserted into the canopy of the tree where members extending from the probe or arm engage the fruit in close proximity to the stem. Such engagement, following continued movement of the probe or arm, provides for generating a picking pressure between the individual fruit and the tree. Such pressure being preferably produced at, or in close proximity to, a terminal end of the stem where the fruit actually attaches to the tree. While much effort has been expended attempting to create a machine based upon the `penetrate and engage` method, very little effort has been extended on creating an efficient and productive picking finger assembly which may operate with such machines. Your applicant has spent considerable time and effort in creating, developing and reducing to actual practice both a practical picking finger assembly and a practical harvesting machine which makes use of such picking finger assemblies.
Applicant's prior U.S. Pat. No. 5,161,358, is the best example of a functional picking finger assembly. While functional, this reference relies upon a complicated design having many working parts. This early design required two (2) separate and distinct tension member assemblies which individually controlled distinct directional finger displacements. Both of these tension member assemblies were complicated.
Various attempts have been made to provide a canopy penetration machine capable of harvesting extremely high percentages of fruit from a tree while minimizing damage to the tree. These attempts have been less efficient than desired primarily due to the construction of the picking member (picking finger assembly) employed thereon. As such, it may be appreciated that there continues to be a need for a canopy penetration mechanical harvesting machine which will harvest a high percentage of the fruit from the tree while inflicting minimal damage to the tree. The present invention provides for canopy penetration machines which substantially fulfill these needs.